[gentoo-amd64] Re: NVIDIA 100.14.19 + xorg-server 1.4.0.90 +xorg-x11 7.3 = blackscreen after every restart

[Duncan <1i5t5.duncan@cox.net>]

B Vance <anonymous.pseudonym.88@gmail.com> posted
1198287150.5803.30.camel@ShadowAerie, excerpted below, on  Fri, 21 Dec
2007 20:32:30 -0500:

> I can't change to console mode.  The only key presses that appear to do
> anything are ctrl-Alt-Del.  The screen goes to black and the drive light
> flickers.  Beyond that it seems to be dead as a door-nail.

Well, if it takes the 3-finger salute, it's not dead.  init, which 
handles that sequence, remains alive, and can initiate the restart 
sequence (init level 6), with the shutdown scripts running so it can run 
bash and the like.  (That's good, as it least it means you get to shut 
down gracefully and don't endanger any data not yet written to disk.)

It would appear to be X that's dead, not the machine as a whole.

You say you can't switch to console mode, but that can mean different 
things to different people.  Does that mean you've tried Ctrl-Alt-F1, 
etc, to see if the VT switcher works?  Also try Ctrl-Alt-Bkspc, which 
should (unless you've disabled it in your xorg.conf) kill X and return 
you to a console prompt.

If none of those work directly, do you have magic sysrq turned on in your 
kernel?  CONFIG_MAGIC_SYSRQ, located under the kernel hacking menu in 
menuconfig.  If you are running a kernel with that configured in, you 
have a few more options as well.  

Even when the three-finger-salute doesn't work (of course, if it does, 
use it), you can still try Alt-Sysrq-S (emergency-sync filesystems, do 
this three times to be safe), Alt-Sysrq-U (unmount what can be unmounted, 
remount-read-only the rest), Alt-Sysrq-B (reboot).  That's handled 
directly by the kernel, so as long as it isn't too far gone, you can 
still avoid most problems of an unclean shutdown.  Of course, if the 
kernel is gone too, or at least gone far enough it doesn't trust itself 
to reliably write anything to the disk lest it write in the wrong place, 
this won't work, but it's always worth a try if Ctrl-Alt-Del isn't doing 
anything.

However, that's for when things get /real/ bad.  Since you can still do 
Ctrl-Alt-Del, you don't have to try the Alt-sysrq-s,u,b thing.  There 
remain a couple other useful sequences to try, however.

Alt-sysrq-k (SAK, secure-access-key/system-attention-key) normally kills 
everything running on the current virtual console; init normally restarts 
the login daemon after that, giving you a chance to log back in.  This 
may work.  Try Ctrl-Alt-F1 to switch to the first VC if necessary after 
that.

Alt-sysrq-r (unRaw the keyboard mode) can also help, at times, 
particularly when X crashes.  If your VT-switcher keys (Ctrl-Alt-F?) 
aren't working, sometimes that'll get them working again, so you can get 
a console to work in.

If none of that is working, then the system is in pretty bad shape 
regardless, and initiating shutdown (either c-a-d or alt-sysrq-sub as 
necessary) is probably best anyway.  However, at least in my experience 
it's rare that ctrl-alt-del works if I can't get a console using one of 
the methods above, so given that it /is/ working for you, it's fairly 
likely you can get a console /one/ way or another.  Of course, that's 
assuming you hadn't already tried all that, but you didn't mention it, so 
I figured it's worth the shot.

-- 
Duncan - List replies preferred.   No HTML msgs.
"Every nonfree program has a lord, a master --
and if you use the program, he is your master."  Richard Stallman

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